﻿#region Copyright and License
// Copyright 2010..2016 Alexander Reinert
// 
// This file is part of the ARSoft.Tools.Net - C# DNS client/server and SPF Library (http://arsofttoolsnet.codeplex.com/)
// 
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//   http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#endregion

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;

namespace ARSoft.Tools.Net.Dns
{
    /// <summary>
    ///   Updateable Resolver HintStore using a local zone file for the hints
    /// </summary>
    public class ZoneFileResolverHintStore : UpdateableResolverHintStoreBase
    {
        private readonly string _fileName;

        /// <summary>
        ///   Creates a new instance of the ZoneFileResolverHintStore class
        /// </summary>
        /// <param name="fileName">The path to the local zone file containing the hints</param>
        public ZoneFileResolverHintStore(string fileName)
        {
            _fileName = fileName;
        }

        /// <summary>
        ///   Saves the hints to the local file
        /// </summary>
        /// <param name="zone">The zone to save</param>
        protected override void Save(Zone zone)
        {
            using (var fs = File.Open(_fileName, FileMode.Open))
            {
                using (StreamWriter writer = new StreamWriter(fs))
                {
                    foreach (DnsRecordBase record in zone)
                    {
                        writer.WriteLine(record.ToString());
                    }
                }
            }
        }

        /// <summary>
        ///   Loads the hints from the local file
        /// </summary>
        /// <returns></returns>
        protected override Zone Load()
        {
            if (!File.Exists(_fileName))
                throw new FileNotFoundException();

            return Zone.ParseMasterFile(DomainName.Root, _fileName);
        }
    }
}